(1) Field of the Invention
This invention relates to a filter manufacturing apparatus and a filter manufacturing method, and more particularly to a technique of manufacturing color filters by inkjet printing for use in liquid crystal displays or electronic paper.
(2) Description of the Related Art
Conventionally, there is a manufacturing method by photolithography as a method of manufacturing liquid crystal color filters. Manufacturing color filters by photolithography can provide filters with high quality in positional precision. However, this requires numerous steps such as mask baking, cleaning and chemical treatment for each filter color.
So, research has been made on a method of manufacturing color filters by inkjet printing in recent years. Compared with photolithography, inkjet printing can reduce manufacturing steps and can manufacture filters at low cost. Patent Document 1 (Japanese Unexamined Patent Publication H9-138306), for example, discloses an apparatus for manufacturing color filters using an inkjet apparatus of the one-pass type.
However, the conventional example with such construction has the following problems. The nozzle pitch of the inkjet head is standardized in the industry, and the arrangement pitch of filters does not usually agree with the nozzle pitch. In order to set the arrangement pitch of filters to positions of an integral multiple of the nozzle pitch, the inkjet head is inclined to match the cosine component of the nozzle pitch with the arrangement pitch of filters. In this case, it is necessary to adjust printing timing of each nozzle individually, which makes control complicated. An angle of inclination of the inkjet head must be changed whenever the filter pitch of a printing medium is changed, which requires a time-consuming adjustment.